This invention relates to gelled fish products commonly referred to as "Kamaboko" type products, and to a vegetable protein composition which is an acceptable ingredient for gelled fish products.
"Kamaboko" is an immensely popular food in the Japanese diet and generally comprises an elastic, gelled, heat-pastuerized fish product. "Kamaboko" is made by separation of fish muscle, which is washed to remove blood, pigments and fat. The washed fish flesh is minced or reduced to a pulp and ground with other ingredients such as starch, sugar, egg white, salt and flavorings such as "mirin" and various flesh extracts. The resulting fish paste is then formed into the desired shape and cooked. There are three main types of "Kamaboko" products including Kamaboko, Chikuwa, and Agekama, each having its own shape and a specific manner of cooking associated with each type of product. For example, steaming is the cooking method of choice for most types of Kamaboko, whereas, broiling is used mainly for Chikuwa, and deep fat frying is used for Agekama.
The distinctive eating characteristic of "Kamaboko" type products is its elastic quality, called "ashi" in Japanese. This refers to the primary feature of this product wherein if it is subjected to pressure, it becomes indented, but can recover readily to its original shape after pressure removal. The elastic quality of "ashi" of Kamaboko depends on the species of fish used, freshness of the ingredients, as well as the processing techniques employed. Another limiting factor for Kamaboko quality besides texture is color, since a very white color is considered to be essential for a quality product. In spite of the critical importance of texture as a measure of Kamaboko quality, color is equally as critical since this is due primarily to the types of fish flesh employed and their relative whiteness. Unfortunately, many of the types of fish which are considered to be the most desirable from a textural as well as a color standpoint are very much in demand and, therefore, will be in increasingly short supply. This has necessitated the investigation of a variety of ingredients which can be employed as a total or partial replacement for the fish flesh employed in Kamaboko products. For example, U.S. Pat. Nos. 3,955,011 and 3,959,517 describe the production of a fish meat powder for making Kamaboko type products with a gel strength comparable to that of Kamaboko made from fresh fish meat.
Yasumetsu et al in Agr. Biol. Chem. 36, p. 737-744 (1972) has evaluated various types of soybean products in fish paste products. Among the types of soybean products evaluated are soy protein isolates, products which are well known in the vegetable protein processing industry. These products generally have a protein content of 90% or greater and are highly functional in the formation of gelled food products. They, therefore, are ideal candidates as a complete or partial replacement of fresh fish flesh in Kamaboko. Unfortunately, as described by the above authors, the use generally of soy protein isolates has not been successful since they detracted somewhat from the texture and overall quality of the Kamaboko products. The most serious defect encountered, however, with the use of soy protein isolates was the inferior color of Kamaboko products containing soy protein isolates. Kamaboko products containing soy protein isolates generally had a darker color and, therefore, represented a serious departure from color standards considered as a minimum for this type of product. Therefore, in spite of the consideration given to these materials as an ingredient for Kamaboko products they have generally been considered unsuitable as an ingredient, and modification of a vegetable protein isolate to permit use in a Kamaboko type product would represent a significant breakthrough.
It is an object of the present invention to produce a vegetable protein composition which is suitable as an ingredient in Kamaboko products.
It is also an object of the present invention to produce a vegetable protein composition which does not impart an undesirable color to Kamaboko products when used as partial replacement for fresh fish flesh.
It is a further object to produce Kamaboko products containing a vegetable protein isolate as a partial replacement for fresh fish wherein acceptable color and texture of the product is maintained.